St. Agnes is in the Hundred and deanery of Pydar, just inland from the North coast
and the Bristol Channel, and lies to the North of Redruth. (see map reference below).
It is not mentioned in the Domesday Book of 1086, as it was considered part of Perranzabuloe
until 1846. It was in the Carrick district until Cornwall became a unitary authority
in 2009, with civil registration for the parish being in the Truro Registration District
continuously from 1st July 1837.

Villages in the parish include the Churchtown, Trevaunance Cove, Towan Cross, Mithian
and Mingoose. The town of Perranporth is to the North East of the parish. Currently
the area is mainly farmland, but St Agnes Parish was one of the great mining districts
in Cornwall, abounding in tin and copper. As a result, the parish is scant of trees.
The Earl of Cornwall once had a manor at Tywarnhayle. The northern boundary of the
parish is the rugged Northern coastline of Cornwall. St Agnes Beacon is a raised
area of land which was chosen as one of the principal western stations of the Ordnance
Survey.